1. Field of the Invention
The present invention relates to a process cartridge, an image forming method, and an image forming apparatus, all of which are suitably used for electrophotography, electrographic recording methods, and electrostatic printing methods, and the like.
2. Description of the Related Art
For latent electrostatic image bearing members (hereinafter, may be referred to as photoconductor, or electrographic photoconductor) used for electrophotography which is widely used for copiers, printers, and the like, organic photoconductive materials have been generally used so far from the perspective of advantages such as low-cost operation, mass production, and no pollution. However, there are some problems with organic photoconductors, because anti-abrasion and durability of organic photoconductors are inferior to those of inorganic photoconductors.
In recent years, full-color images and high-speed processing of electrophotographic systems have been demanded, and tandem-type full-color image forming apparatuses providing with individual photoconductors for each color toner have been put to practical use. To downsize the tandem-type full-color image forming apparatus, diameter of the photoconductor must be made smaller. For this reason, further improvements in mechanical durability of photoconductors which are primarily represented by anti-abrasion of photoconductors, have become strongly requested.
For a method for improving anti-abrasion of organic photoconductors, for example, an organic photoconductor with a protective layer containing a filler which comprises metal or a metallic oxide provided thereon have been disclosed in Japanese Patent Application Laid-Open (JP-A) No. 01-170951. Except of the method for improving anti-abrasion of a photoconductor itself by providing the protective layer to the surface of the photoconductor, a method for reducing the surface energy of a photoconductor by applying a lubricant to the surface of a photoconductor has been known in the art. For a method for supplying a lubricant to the surface of a photoconductor, for example, there have been proposed a method for applying a solid lubricant using a coating unit such as a brush which is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-162881, a method for supplying a lubricant to the surface of a photoconductor by adding the lubricant to toner as an external additive, which is disclosed in Japanese Patent (JP-B) No. 2859646, and the like. In addition, by reducing surface energy of a photoconductor through the use of a lubricant, it is also possible not only to reduce abrasion of photoconductor but also to improve transferring rate and prevent occurrence of abnormal images such as transferring omissions.
It is also possible to reduce abrasion of a photoconductor by coating a metal-containing compound on the surface of a photoconductor by means of a metal-containing coating unit to reduce surface energy of the photoconductor and protect the photoconductor from strong charging hazards such as AC charge.
However, there are some problems with an image forming apparatus which comprises the metal-containing compound coating unit as shown below: (1) when a charge roller is used in combination with the metal-containing compound coating method for use, there is no problem involved initially, however, with the lapse of time, smear of metal-containing compound occurs on the charge roller, causing charge nonuniformity and resulting in abnormal images. (2) when a metallic soap is used as the metal-containing compound in combination with a toner having small particle diameter, there is no problem involved initially, however, with the lapse of time, abrasion of blade edge according to blade cleaning methos considerably increases, resulting in degraded cleaning durability.
Accordingly, in an image forming apparatus which comprises a metal-containing compound adhesion unit configured to make a metal-containing compound adhere on the surface of a latent electrostatic image bearing member, an image forming apparatus enabling preventing smear on the charge roller, reducing abrasion of blade edge and forming excellent images in stable conditions and relevant techniques thereof have not yet been presented so far, and there are demands for quickly providing such an image forming apparatus.